It is known, particularly in the United States, to supply such stays in a form whereby the links and arms of the stay are mounted on the window and the base of the stay is mounted on the window frame. The frame is located and secured in the building and the builder then presents the window into the frame and slides a slider into a channel on the base. He then secures one of the links to the base using some form of releasable attachment. Examples of such attachments are illustrated in U.S. Pat. Nos. 3,457,675 and 4,593,431. That shown in the first of these Patents comprises a locking device slidably mounted on the link which engages in a recess of an upstanding stud on the base. While this works in principle, it is quite expensive to manufacture and assemble and is susceptible to damage during transit or jamming if not used for a long period of time. In this latter connection, it should be understood, that many of these stays are manufactured with a view to a short life expectancy and it is anticipated that the stay will require subsequent release to allow for repair or retro re-fitting.
In U.S. Pat. No. 4,593,431 the releasable connection is provided by a circular circlip which sits in an expanded position in a recess in a stud to hold the link to the base but which can be compressed into that recess when the link is subjected to a force which makes it travel longitudinally with respect to the stud. Here the circlip can come off the stud or it may become jammed as grease and dirt build up in the recess. Manufacture is also once again quite expensive.